An update on the pathogenesis, inflammation, and metabolism in hirsutism and polycystic ovary syndrome

Hirsutism is a common endocrine disorder, defined as increased growth of terminal hairs in a male pattern. Hirsutism is most often caused by polycystic ovary syndrome (PCOS), whereas only 5% patients are diagnosed with rare endocrine diseases. PCOS may be considered a multiorgan disease causing not only increased adrenal and ovarian sex hormone secretion but also changed secretion of gonadotrophins, growth hormone, and adrenocorticotrophic hormone (ACTH) from the pituitary. The majority of patients with PCOS are insulin resistant and PCOS is characterized by an increased inflammatory state with abdominal obesity and increased secretion of interleukins, chemokines, and adipokines. PCOS is therefore associated with an increased risk of the metabolic syndrome and type 2 diabetes (T2D). Patients with hirsutism present with increased bone mineral density despite decreased D-vitamin levels. The etiology to hirsutism and PCOS is most likely multifactorial including both genetic and environmental factors such as increased fetal stress and intrauterine growth retardation. In the present review, we give a comprehensive overview of the pathophysiology and multiple endocrine disturbances of hirsutism and PCOS.